The present invention relates to a method for manufacturing a seat post of a bicycle, and more particularly to a method for manufacturing a seat post of a bicycle which has a seat support integrally formed on a top end of the seat post.
A conventional bicycle seat post is shown in FIG. 6. A reduced diameter potion R is formed on an upper end of the seat post S. A lower support L is fixed on an upper end of the reduced diameter portion R by means such as welding or a screw joint. A seat frame F of a seat cushion C is clamped between an upper support U and the lower support L which are clamped together by a clamp plate P and a bolt B. One disadvantage of manufacturing this conventional seat post is that the lower support L is manufactured separated so that the manufacturing process is complex and time consuming, especially the process for welding the lower support L to the reduced diameter portion R of the seat post S.
Another conventional manufacturing method is that the lower support L and the seat post S are made by a casting process so that they are integrally formed. Though the lower support L and the seat post S are integrally formed, the manufacturing process is still very complex, the weight of the seat post is large which is adverse for shipping and transportation. In addition, a porous structure may be inadvertently formed in the casting process so that the strength of the connection between the lower support L and the upper end of the seat post S is low.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional bicycle seat posts.